POS0915 MYOSITIS-SPECIFIC AND ASSOCIETED ANTIBODIES, ESPECIALLY ANTI-ARS ANTIBODIES AND ANTI-Ro52 ANTIBODY MAY PREDICT THE CHARACTERISTICS AND FIBROSING PROGRESS OF INTERSTITIAL LUNG DISEASE WITH DERMATOMYOSITIS / POLYMYOSITIS
Authors: S. Nakashima, H. Nakaishi, H. Shimada, R. Wakiya, M. Kato, T. Miyagi, K. Sugihara, R. Mino, M. Mizusaki, T. Kameda, H. Dobashi
Journal: Annals of the Rheumatic Diseases (2022)

Background Myositis-associated antibodies (MAA) and myositis-specific antibodies (MSA) have been associated with clinical manifestations of dermatomyositis and polyneuropathy, including interstitial lung disease (ILD), myopathy, malignancy, arthritis, and skin rashes. Among them, anti-ARS and anti-MDA5 antibodies are strongly associated with complications of ILD that are associated with life expectancy. It has been reported that anti-Ro52 antibody affects severity of myositis and ILD. (1) Based on these findings, it is possible that autoantibodies possessing features of ILD associated with dermatomyositis and polymyositis may be predictive. Objectives The purpose of this study is to clarify the relationship between MSA/MAA and clinical features of ILD complicated by dermatomyositis and polymyositis. Methods We retrospectively analyzed IIMs patients diagnosed according to Peter &amp; Bohan’s diagnostic criteria in our hospital from 2011 to 2018. The presence of 14 MSA / MAA (Jo1, PL12, PL7, EJ, OJ, KS, Mi2, MDA5, TIF1γ, SRP, PM-Scl70, 100, Ku, Ro52) was measured using ELISA (MESACUP, MBL, Japan) and line blot (EUROLINE myositis profile3, EUROimmun, Germany). Clinical characteristics, including HRCT imaging findings, were extracted from medical records. HRCT imaging findings were analyzed by multiple radiologists. The association between the extracted clinical features and the MSA / MAA held was analyzed. Results Seventy-eight cases of IIM were included in the analysis. The frequency of ILD complications was 53/78 (68%), and 60% of ILD complications were ARS antibody positive. The complication rate of ILD in MDA5- and ARS-positive cases was 100% (3/3 cases) and 94% (32/34 cases), respectively. These MDA5- and ARS-positive patients with ILD had rapidly progressive ILD. One of the three MDA5 antibody-positive RPILD cases died, but none of the four ARS antibody-positive RPILD cases died. However, in patients with multiple MSA or MAA including ARS, three case had rapidly progressive ILD, and none died. n the analysis of the presence of Ro52 antibody, it was detected in 46% (36 cases) of all cases, but in 74% of anti-ARS antibody positive cases. In the analysis of ILD patterns by radiologists using HRCT, fibrosing NSIP (fNSIP), fibrosing OP (fOP), and UIP were the most frequent in that order. analysis of the association between ILD patterns and MSA / MAA showed that there was no MSA / MAA associated with each ILD pattern. No MSA/MAA was found to be associated with each ILD pattern. ARS antibody-associated ILD, the most common type of ILD, had a worse prognosis than other MSA / MAA positive ILD. Death due to ILD was observed in 5 patients (PL7: 3cases, PL12: 1case, PM-Scl75: 1case). Oxygen was required for ILD progression in 3 Jo1-positive patients, 1 PL7-positive patients, and 1 PL12-positive patient, respectively. The frequency of UIP, which is considered to have a poor prognosis in other rheumatic diseases, was higher in patients with anti-ARS and anti-Ro52 antibodies. Conclusion The prognosis of anti-ARS antibody-positive lLD associated with dermatomyositis and polymyositis was associated with fibrosis by analysis of HRCT patterns, and the prognosis was confirmed to be poor.In addition, the UIP pattern, which is strongly associated with fibrosis, was found to be associated with anti-Ro52 antibody. In the treatment of ILD, which is strongly associated with the prognosis of dermatomyositis and polymyositis, it may be necessary to consider antifibrotic treatment for patients with anti-ARS antibody and anti-Ro52 antibody positivity. References [1]Tamara Vojinovic et al. Predictive Features and Clinical Presentation of Interstitial Lung Disease in Inflammatory Myositis. Clinical Reviews in Allergy &amp; Immunology (2021) 60:87–94 Disclosure of Interests None declared